Wire stretcher



1941. E. A. ROBERTSON 2,251,413

WIRE STRETCHER Filed Jan. 12, 1940 IN VENTOR.

\ ATTORNEY.

Patented Nov. 4, 1941 -UNITED STATES PATENT QFFlQE WIRE s'rnn'ron'na Edward 'A. Robertson, Chehalis, Wash. Application January 12, 1940,;se1-i'a1 No; 313,492 toiaims- (01. 254 77.)

This invention relates to a wire stretcherto be used in tightening slack wire in 'old and. new fences and more particularly relates to the provision of means for utilizing a conventionaipinch bar having a pair of drawing claws as a wire i stretcher. I i

As is well known to those acquainted. with the construction of wire fences, such as-the ordinary three or four strand barbed-wire fence, a wire cannot be drawn sufficiently tight unless some sort of a lever is used or some power stronger than man power is available. There have been designed, therefore, a variety of wire stretchers, most of which are equipped. with means for ob-' taining a purchase on the side of a fence .post and which by means of a plurality of pulleys or a rack and gear or some other mechanical arrangement can exert considerable drawing poweron a Wire across the fence post so that, when tight, the wire may be secured to the fence,'as by a staple. In designing these wire stretchers the manufacturers apparently had more in mind the tightening of wire during the stringing of .anew fence than the taking up of loosened orslack wire'on old fences, with the result thatexisting wire stretchers are more easily handled when that side of the post opposite to that from which the wire is being pulled is free of interfering wires, a condition which may exist when building new fences but which does not exist'when drawing up slack wires in old. fences. Thus, in stringing .the wires in a new fence a wire will be an.- chored at the starting post and the spool of wire carried to the next post. The fence builder will work from that side of the second post opposite to the side adjacent to the beginning post, and there being no interfering wires because the spool of wire has been laid to one side, he may maneuver the wire stretcher at will, Where, however, the fence wire is already strung, as in an old fence or where in building a new fence the wire is strung to several posts and then tightened, it becomes necessary-for the wire stretcher to work at one side of the wire which it must tighten, and under these circumstancesexisting wire stretchers provev cumbersome and difficult to handle. The fact is that there is no Wire stretcher on the market which can quickly and efficiently tighten slack wires in old fences and those which will properly tighten wires in the building of a new fence are neither simple nor inexpensive to build. With the above conditions and requirements in mind, the first object of this invention is toprovide a wire stretcher which possesses *sufiicient mechanical leverageto permit manual operation and which utilizes as its principal element a conventional pinch bar of the type that has a pair of drawing .claws on a hooked end. For many years there has been sold throughout'the United States "large quantities of such pinch bars which cut in its base wall, through which the shank of such a pinch bar may be drawn, together with a holding means such as a nut and bolt mounted through the outer edges of the opposite side walls of the'channel iron for holding the pinch bar in 1 I assembled relationship therewith. By this arrangement a' farmer isrequired to purchase-only the channel iron in order to convert a pinch bar which he already has into a wire stretcher. If he lacks sucha pinchbar, the combined selling price of the pinchbar and channel iron will create less sales resistance than otherwise would be the case because of the value of the other uses to which the pinchbar may be put. j The'second object, of this invention is to providea wire stretcher which has means for engaging-the opposite sides of a wire at a selected distance between i the points of engagement whereby bending the Wire from itsjnormal longitudinal direction; which in the'case of strung wire on a fence is generally horizontal, will provide' the wire stretcher with a firm purchase on the wire so. as to prevent longitudinal slippage. One pf'thefeatures of this invention is the utilization of a conventional pinch bar of the household size 'in conjunction witha channel iron having a; V'-shaped opening pointed in a direction generally opposite ,to'the V-shaped opening be tween the claws of such a pinch bar whereby the V-shaped opening on the channel iron may be hooked over the wire to be tightened and the opening between the'claws of the pinch bar may be hooked. under it. By properly Working the pinch bar after the wire has been so engaged, the wire will work tightly into these oppositely directed, V-shaped openings so as to prevent longitudinal'movement of the wire with respect'to the wire stretcher. This simple construction eliminates the employment of gripping jaws and the like. I I v A furtherobject of this invention is to provide an improved means for establishing engagement between thiswire stretcher and. the side of a fence post. As will: appear more clearly in the disclosure, it is important that the end of the wire stretcher which is brought into contact with the post be pointed toward the post at an angle of not less than 45 degrees between the axis of the wire stretcher and the vertical side of the post in order to bite the post and avoid slipping. If the lever were laid flush against the side of a post at the beginning of the tightening operation there would be a tendency for the end of the lever engaging the post, particularly in the case of a steel post, to slip downwardly and to drop the wire out of alignment. One of the features of this invention is the lengthening of the channel iron sufiiciently so that when the drawing claws are laid against the fence post, the axis of the wire stretched will form an angle of about 45 degrees with the post. As the stroke continues, the angle between the pinch bar and the post approaches a right angle and the strengthof forces tending to displace the wire stretcher with reference to the post is steadily diminished. A feature of the channel iron relating to this aspect of the invention is a cut-out portion in the end which will engage the post, the edges of the cutout portion being sharp so that these edges together with the contour of the cut-out will assist in providing a bite on any kind of post, whether it be wood, concrete or steel.

These and such other objects as may hereinafter appear are obtained by the embodiment of this invention shown in the drawing comprising one sheet wherein;

Figure l is a .view in perspective of the channel iron;

Figure 2 is a side view of the assembled wire stretcher as actually used in drawing up wire on a fence post; and

Figure 3 illustrates diagrammatically the extent of the drop of a wire during various tightening operations.

One embodiment of this invention is disclosed in the drawing wherein, referring particularly to Figure 2, may be seen a pinch bar In which is held in assembled relationship with a channel iron I2 by means of passing the handle end I4 of the pinch bar through a hole I 6 in the channel iron I2 as far as the curved portion or prying foot I8 to which is afilxed theconventional pair of claws of the pinch bar. Referring to Figure 1, the channel iron I2, comprisinga bottom wall 22 and opposite side walls 24 and 26, has a nut and bolt 28 and 30 mounted between the side walls 24 and 26 in order to hold the shank of the pinch bar I0 in assembled relationship with the channel iron I2. It will be observed that the upper or forward edge of the hole I8 is depressed at 32 while the lower edge is raised at 34 in order to assist in firmly seating the curved portion I8 of the pinch bar I0. By this arrangement a conventional pinch bar is quickly converted-into a wire stretcher.

The second feature of this invention is the use of oppositely directed slits for obtaining a purchase on the wire to prevent longitudinal movement of the wire during a tightening operation. The claws of the pinch bar are used as one gripping means while the other-gripping means is provided by slits 36 and 38 cut into the opposite side walls 24 and 26 of the channel iron I2 by bending outwardly the wings 40 and 42. In order to use the wire stretcher in drawing up a slack wire, as contrasted with drawing tight a wire on a new fence, the user when standing on the near side of the fence shown in Figure 2, will slip the slit 36 over a wire 44 and then move the pinch bar in a clockwise direction as viewed in that figure to a point where the claws 20 may be slipped under the wire. The wire stretcher is then moved up to a post 46 where the end 48 of the channel iron I2 makes contact and acts as a pivot. As the user moves the pinch bar downwardly, the wire 44 quickly works its way into the slit 38 and between the claws 28 whereby longitudinal movement of the wire is stopped. When this occurs, further downward movement of the pinch bar handle I4 will draw the wire 44, as viewed in Figure 2, toward the left, thereby tightening the same. It will be observed that a user will always use the slit, 36 or 38, which is away from his body and adjacent to the fence. This is important in that it enables him to operate the wire stretcher without interference with the stretched wires.

The speed with which this wire stretcher may be used will be appreciated, for the combined length of the wire stretcher from the handle I4 on the pinch bar to the gripping edge 48 on the channel iron is such that a user may operate the pinch bar wire stretcher with his left hand and drive a staple at 50 with his right. It is important that the wire stretcher be capable of operation by one man.

Mention has been made of the cut-out portion or biting edge 48 on the channel iron I2. The edges of this cut-out portion 48 are sharp and in conjunction with the curvature provide an all round means for engaging any type of a fence post for resisting slippage between the wire stretcher and the post. However, the cut-out portion and its sharp edges would not alone be sufficient to prevent slippage if the wire stretcher were so designed that the stroke would start with the stretcher substantially parallel to the side of the post as is the case of the line 52 in Figure 3. If some means for holding. the wire were provided in a straight lever such as 52,, the end of the lever engaging the post at 54 would tend to move downwardly along a resultant of evident forces. In order to avoid this defect, a pinch bar having the hooked end I8 is employed in conjunctionwith the end portion 56, see Figures 1 and 2, of the channel iron. By means of'the hooked end I8 of the pinch bar I0 andthe portion 56 of the channel iron I2 there is established an angle a in Figure 3 which makes it possible to commence the stroke of the wire stretcher when the pinch bar is in the position 58 and the claws 28 are engaging the wire 60 at 62. As the wire stretcher moves downwardly from 58 through an angle b to the horizontal position 64 the angle between the biting element 48 of the channel iron I2 and the post changes from 45 degrees to degrees. Experiment has shown that in this range there is very little slippage between the biting edge and the post, even when the latter is a steel post having only the thickness of one of its walls engaged by the w re stretcher. This oiiset relationship between the claws of the pinch bar and the axis of the wire stretcher is an important feature of the invention.

Further considering Figure 3 it will be noted that this disposition of the claws 20 at a point substantially outside of the axis of the wire stretcher makes it possible to commence the stroke of the wire stretcher at 58 and move down to the horizontal position 64 while pulling the wire 68 through the distance x and dropping the wire by only the distance y. It is desirable that a wire stretcher draw up the wire along a horizontal line without greatly raising or lowering it. His evident that a straight wire stretcher such as 52 having a means in its axis for engaging the wire 60 at 62 is inferior to applicants stretcher in one of two respects. If it draws the wire through the angle a so as to pull the wire through the comparatively long distance a: and drop the wire by only the distance y it will work under the disadvantage of not obtaining a secure bite on the post, as discussed in the preceding paragraph. On the other hand, if such a wire stretcher starts with the position 58 engaging a wire 66 at 68 and moves through the angle b, it will only draw the wire up by a distance m while dropping the wire by a distance n. From studying Figure 3 it will be seen that the positioning of the gripping means at a point substantially outside the axis of the wire stretcher is important in that it provides the best grip on the fence post while drawing up the wire for the maximum distance with the least drop.

The embodiment of this invention shown in the drawing is but one of several which could be utilized to incorporate applicants idea in a wire stretcher. For example, it is evident that by redesigning a pinch bar one could insert a second pair of jaws in the shaft of the pinch bar in place of the V-shaped openings 36 or 38 and convert the pinch bar into a wire stretcher. It is evident that while the channel iron, which may be referred to as an adaptor plate, is useful as one means of easily holding a pinch bar, other means could be devised for holding a pinch bar which would be the equivalent of such a channel iron and enable a conventional pinch bar to function as a wire stretcher. Equivalents for the concept of gripping a wire on opposite sides at a selected distance by a member adapted to be pivoted or fulcrumed on the side of a post so as to tighten the wire between such holding means, as for example oppositely directed sharp edges, could be devised.

Having thus described the invention, what I claim as new and desire to secure by Letters Patents of the United States is:

1. A wire stretcher of the character described comprising, in combination, a pinch bar having a hooked pair of claws at one end and means cooperating with said claws for holding a wire against longitudinal movement, said means comprising a channel iron having a bottom and opposite side walls adapted to hold in assembled relationship a portion of the shank of the pinch bar, there being a wedge-shaped opening in a side wall of the channel iron whereby a wire drawn between the hooked claws of the pinch bar and through said wedged-shaped opening may be held tightly against longitudinal movement.

2. A wire stretcher of the character described comprising, in combination, a pinch bar having a hooked pair of claws at one end and means cooperating with said claws for holding a wire against longitudinal movement, said means comprising a channel iron having a bottom and opposite side walls, means on said channel iron for engaging a wire in cooperation with the hooked claws of the pinch bar, and a hole in the bottom of the channel iron through which the pinch bar is passed and a secondary locking means for holding the shank of the pinch bar within the channel iron whereby the pinch bar is held in assembled relationship with the channel wire.

3. A wire stretcher of the character described comprising, in combination, a pinch bar having a hooked pair ofclaws at one end'and means cooperating with said claws for holding a wire against longitudinal movement, said means comprising a channel iron having a bottom and oppositely disposed side Walls and a hole in the bottomof the channel iron at a distance from one end thereof such that the positioning of the pinch bar in said hole will create an angle between the axis of the pinch bar and a line from said end of the channel iron to the claws of about 45 degrees, whereby through a preferred stroke of the wire stretcher, a wire will be drawn a maximum distance with a minimum drop.

4. A wire stretcher of the character described comprising, in combination, a pinch bar having a hook on one end at'an angle of or more with the shank of the pinch bar, the end of said hook being equipped with pulling claws, a member mounted on said pinch bar in a predetermined relationship, slits in said member for holding a wire in cooperation with said pulling claws and means on said member for obtaining a purchase on a fence whereby the pinch bar may be used as a wire stretcher.

5. An adaptor plate for utilizing a pinch bar having a hook on one end forming an angle of less than 99 with the shank of the pinch bar, the end of said hook being equipped with pulling claws, as an element in a wire stretcher comprising, in combination, means for holding the pinch bar in assembled relationship and wire gripping means on said adaptor plate.

6. An adaptor plate for utilizing a pinch bar as an element in a wire stretcher comprising, in combination, a channel iron having a base and two oppositely disposed sides, a hole in said base to pass the shank of a pinch bar at a seletced distance from an end to be used as a pivot point on a fence and a slit in one of said side walls formed by an outwardly directed wing portion.

EDWARD A. ROBERTSON. 

